Process and apparatus for washing curd for cottage cheese



R. B. WOLF April 18, 1961 PROCESS AND APPARATUS FOR WASHING CURD FOR COTTAGE CHEESE Filed June 50, 1959 .N .DI

INVENTOR AYMOND B. WOLF ROBERT CALVERT ATTORNEY.

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.` .l. SmmwpmGm/LI United States Patent *O 2,980,538 PRoCE'ssAND APPARATUS non WASHING CURD FOR COTTAGE CHEESE Raymond B.- Wolf, San Francisco, Calif., assignor t o The Borden Company,New York,.N.Y., a corporation of New. Jersey a Firearm-1e 30, 1959, ser. No; 624,059"

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This inventionrelates to the handling and processing of 'curd 1in' the makingoffcottage cheese. Y

The inventionfisuuseful. in` decreasingy the hand labor currently required in the washing and draining of liquid from curd for cottage cheese and in avoiidingrunnecessary4 exposure of the curd to oxidation and to contact with lairborne microorganisms during the time required for chilling.

The liquid to be removed from the curd is whey at the start and later whey diluted with water in continuously increasingr proportion up tov almost infinite dilution. Whey is used herein toinclude both these types of liquids.

The invention provides'v an effective, quick and economical process of removing'whey from the. curd, for chilling the curd. to thenecessary firm condition with a minimum time of exposure to molds, bacteria, other organisms and oxygen ofY the air, and dewatering the chilled-curd, all in a continuousoperation requiring no hand labor from Vthe time the. curd-whey mixture'is delivered from thev making vat untilthe. processed curd is ready for compounding with cream and the other components into the tnishedzcottagecheese.

This-inventionincludes' the herein describedf process and machine for handling: the. curd in making cottageV cheese andmore particularly, means for rapidly and economically washing and cooling the curd, as by moving the curd' and contained whey in layer form alternately down and up in a massof cold water and also continuously forward, and subjecting the layer at intervals to Patented Apr. 18, 1961 curd passes to the next step. The belt with the curd thereon then passes over a series of eccentrically mounted rotated, i.e., power driven rollers 22'. These subject the belt and the curd thereon to a combined vibrating and alternate risingand lowering, so as to alternatelyv immerse the curd layer inthe refrigerated water tank 32 for cooling and raise the curd for draining.

Disposed both above and below the belt and the curd layer thereon, during the use of the machine, are a series of water sprays. Part of the recovered water 30 is used in' sprays 24 and 25, as a prerinse. The rest of thiscold Ice water 30 goes to the drain. Line 26 delivers refrigerated water from coolers (not shown) to sprays 27 and line 31l delivers refrigerated water to sprays 29'.

The eccentrically mounted rollers 22 are at such a level' that, at their upper parts, they alternately dip below and rise above the level of cold water 3G'. At the positionsl of sinking` of the. belt onthe said rollers, it submerges the curd. in the refrigerated washV water 30 which contains. some whey and alternately raises the curd out of the Water for direct contact with the refrigerated water from the sprays 27 and 29; After repeated up and down movement by the saidA rollers with accompanying submerging in the refrigerated Water and subsequent draining andwashingY with the sprayed water, the curd is. de#

liveredV over the change of direction drum 34, so that the curd falls, as shown at 36, in `large part through chute 3S to a perforated orl second woven wire belt 40' for passage between this belt serving as a draining conveyor and an overriding; belt converging therewith, as the two belts at their adjacent reaches aremoved towards the leftv end. ofthe` mechanismy shown in' the figures. The belts:

are forcedvtogether against the W'et curd, sandwiched.

` belt 14 imemdiately to the right of the'hopper 12, receives the whey or water and line curd suspended therein; The

liquor drainsffrom the curd caught on this screen, thel screen. being of mesh'size to allow the whey or water to pass therethrough butto retain the line particles of curd.:

`.' The accumulated curd onscreen 14 andfne settlings on a. draining surface, to decrease the moisture content thefbottom offtankjZ areremovedfat intervals by-any` usual means (not. shown). A part of the lines which pass through the belt 1 4. at positions above tanks 32 andz 56' do not settle, particularly. since the rollers 22 cause,

vsome agitation. The unsettledlines go through outlet line 58 and finally into. the line'62 which delivers the wet fines.v to `collecting vessel 64.V `Herea rotarylter with iilten'ng -surface 66vr filtersv water away to outlet 68`and collects the curd particles on tliesurface 66 `for delivery/against thescraper knife Y69 toftank 70 for lreceiving lines'. recovered are placed in hopper 52. Y

The exces'sof refrigerated washwater that accumulates in tank" 32 from the` sprays 27. and 29` overflows thru overlow.'linen'.` Part of thisfoverow enters line'58 and v returns asta'prerinse thru sprays 24 and 25. lThe bal- 14 or `any type of Vfilteringsupportwithshoulderslll'exp tending.upward from each'sidefthereofjas to a distance of approximately? inches, ,the shoulderspreventing the. mix

10 from falling. over.:v thesides of. the. support.

.The cross br orlblade,,18restricts.the backward flofwl "thejwet curd so. dliverecltofthe,-belt. ;-'l7he. adjustable blade 2li spreads the cheese curd -onethe belt-.jas-alayer of desired thickness'.r ,'lll'feccentric -roller.-2j1 vibrates;

`anceof this` water is discarded Ythrough line 62.

Fllapper'"A75`dislodges' adhering curd fromthe belt 14 whenfthe, major part of the curd has been'removed. Conf ventional means (not shown) drive this flapper, so that belt 'andshakes orwaterJ-before the l `andpasses rthrouglrline-62 from this collector to'the;D

description. offitthat-z has;` been givenl.

The temperature of the water supplied to sprays 27 and 29 should be very low. The nearer the temperature is to the freezing point of water so long as the water is fluid, the more quickly the water chills and firms the curd and, Aas a result, the more it speeds up the washing and increases the shelf life of the finished cottage cheese. While we may use temepratures within the range about ll0 C. or somewhat higher we use for best results temperatures around 1?-5 ordinarily about 2 C.

The pressure forcing the squeeze rollers 44 and 46 `in the direction of each other and against `the layer of curd therebetween supported on belt 40 is varied with the thickness of the layer of curd being dewatered by the resulting squeezing action. The thicker the layerofcurd at this stage, the higher is the pressure forcing the rollers 44 in downwardly direction and rollers 46 upwardly. The pressure is adjustedin any case so that the finished dewatered curd going into hopper 52 contains the proper proportion of moisture for subsequent blending with cream. This is the proportion that causes thecream to film completely over each particle of the curd, in making the finished cottage cheese. The weight of the rollers 44 or even of the belt 42 alone is often adequate, to give the dewatering to the desired commercial percentage of moisture in the curd to be mixed with the cream.

The up and down and forward movement to which the layer of curd on the belt 14 is subjected in the alternating immersions and spraying with the refrigerated water give a'quick and uniform cooling of the cheese curd over all of the surfaces. The vibrating. action which the rollers 22 createcontinuously exposes fresh surfaces of the lumps of curd to the action of the refrigerated water.

While various rates of movementmay be used, we

move the belt 14 and curd thereon (l) up and down at a mean rate of about 20 to 30 revolutions per minute and (2) with a horizontal or forwardly component ofl velocity, that is, to the right for the upper reach of the belt-in Fig. l, of about l to 20 feet a minute. These rates are subject to considerable variation. v

While the various sprays may be omited, such as omission makes the process and machine less effective and less rapid, increases the amount of cold water required for washing the curd, and gives a product of inferior quality as compared to Ythat obtained with the use of the sprays.

The movement of the layer of curd downwardly in the water 30 and also the spraying by sprays 29 1delivering water below the belt 14 loosen the curd 1S, by decreasing the closeness of packing which would otherwise decrease the rate of ow of liquid through the curd.

The process effects a substantial saving of labor. It reduces the total time required for handling and processing the curd, from hopper 12 to collector S2, to less than about 5 minutes and normally only 2 minutes. It improves the quality of the cheese, by decreasing the time of contact of the warm curd with air or air-borne organ- The results include improved avor and ,keeping isms. qualitites of the product.

There-isY no need with this machine, in exposing fresh .Y

surfaces of the curd to the cooling liquid, to stir the cheese with hand implements. There 'is thus saved not only time which, if" extended, leads to undesirable voxidation or other reactions, but also considerable labor of operation. There is nok need to pile curd for drainage, as the dewatering between belts 40 and 42 serves to eEect thev necessary dewatering in a very short period of time, at a pressure of about 0.5-3 pounds per square inch. VThis leaves a curd of water content about 75%-80%, las rer quired by certain statutes. Y Y

The materials ,of construction are those that are usual in like partsLin the handling of food products. Thus Yall the parts must be sanitary and free from rust. kWe use Ystainless steel or rubber where possible. Thus the vars,

steel or of iron surfaced with stainless steel or other noncorrosive material. Other metals may be used to replace stainless steel in certain or al1 parts including iron, aluminum or chrome plated metal. The rollers 44 and 46 and the pressure belt 42 are suitably of Teon, nylon or rubber, at least on their'outer surfaces.

The openings in or meshes of the belt 14 are of Vsize to cause water or whey to drain therethrough but to retain curd particles of all but the finest sizes which, if retained. would interfere objectionably with the draining of water. The openings in belt 40 retain the fines that remain in the curd after the preceding washing but permit drainage of water under the pressure applied by rollers 44 and 46.

A conventional dn'p pan (not shown) is disposed below belt `4t) for returnof expressed fluid to collector 64.

The machine and method are simple and effective in operation.

It is to be understood that it is intended to cover all Vchanges and modifications of the examples of the invena bath of refrigerated water, at a rate to cause vthe refrig-v erated water to move alternatively upwardly and downwardly in the saidA layer, subjecting the curd at positions above the said bath to sprayed refrigerated water, draining the sprayed'water from the curd and repeating these steps until the whey is washed from the -curd and the washed curdis chilled to firm condition.

2. VThe process of claim'l which includes effecting the Vsaid down .and up movement continuous-ly and moving the curd also continuously'with a horizontal lcomponent l of velocity.

the layer in the waterV and raising the layer thereabove, t

means for maintaining the layer of curd in loose condition so as tol promote passage of liquid therethrough, and?l means for draining liquid from the layer of curd.

6. The machine Vof claim 5 including, a filtering coriveyor belt of size of openings to pass whey and water therethrough, means for applying a layer of the curd and whey mixture to the upper surface of the belt, and

meansfor moving the belt downand yup and in part horizontally in a bath of cold water.

7.1 The machine of claim 5, the said means for mainl Vtaining the layer of curd in loose condition including means for forcing water upwardly against the under surface of the said filtering support and through the layer of curdV thereon. v

8. VThe machine of claim 5, the said means for maintaining the layer of'curd in loose condition including eccentrically mounted rollers extending transversely of the support and at aY level near the surface of the water in thek said tank so vthat the' upper surface of each roller is alternately above the surfacejof the water Vand therebelow asthe roller is rotated andmeans for rotating thev rollers, the said support resting lupon therollers and being alternately raisedland loweredthroug'h `the said water as the rollers-rotate 'and the downward movement of the layer of curd in the watercausing the V*water to` rise through the curd'and todecreasefthe closeness of packing of the particlesofthe curd.

9. In Washing whey from curd for cottage cheese and quickly chilling and firming the curd, the process which comprises moving the curd in layer form on a draining support alternately down and up, into and above a bath of refrigerated water, `at a rate to cause the refrigerated water to move alternatively upwardly and downwardly in the said layer, draining the water from the curd, and repeating these steps until the whey is washed ,from the curd and the washed curd is chilled to iirm condition.

10. In washing whey from curd for cottage cheese and quickly chilling and firming the curd, the process which comprises moving the curd in `layer form on a draining support, subjecting the layer of curd at spaced positions to downwardly directed streams of cold water,

as to loosen the curd in the said layer and promote washing of whey therefrom, and compressing the Washed curd to lower the water content thereof.

References Cited in the tile of this patent UNITED STATES PATENTS 821,334 Buskist May 22, 1906 2,505,984 Miollis May 2, 1950 10 2,781,269 Harper et al Feb, l2, 1957 OTHER REFERENCES Sweet Curd Cottage Cheese, University of Illinois College of Agriculture, Urbana, Ill., Circular 445, Januforcing cold water upwardly between said positions so 15 ary 1936, page 8. 

1. IN WASHING WHEY FROM CURD FOR COTTAGE CHEESE AND QUICKLY CHILLING AND FIRMING THE CURD, THE PROCESS WHICH COMPRISES MOVING THE CURD IN LAYER FORM ON A DRAINING SUPPORT ALTERNATELY DOWN AND UP, INTO AND ABOVE A BATH OF REFRIGERATED WATER, AT A RATE TO CAUSE THE REFRIGERATED WATER TO MOVE ALTERNATIVELY UPWARDLY AND DOWNWARDLY IN SAID LAYER, SUBJECTING THE CURD AT POSITIONS ABOVE THE SAID BATH TO SPRAYED REFRIGERATED WATER, DRAINING THE SPRAYED WATER FROM THE CURD AND REPEATING THESE STEPS UNTIL THE WHEY IS WASHED FROM THE CURD AND THE WASHED CURD IS CHILLED TO FIRM CONDITION. 